Can Nishikori overcome his major weakness?

There was disappointment again for Kei Nishikori on Monday, with the world number six forced to retire from his fourth round match against Marin Cilic due to a rib injury.

Nishikori did not look healthy from the outset of his match against the Croat, but soldiered on until he was 6-1, 5-1 down before retiring from the match. It was a bitter pill to swallow for Nishikori, with the absence of Rafael Nadal and Novak Djokovic from the business end of the event opening up the draw somewhat. Unfortunately it’s not the first time that fitness – or a lack thereof – has stymied the Japanese ace.

Having been named the 2008 ATP Newcomer of the Year, Nishikori then proceeded to miss most of the 2009 season due to an elbow injury. It would be the first of many injuries that would hamper his progress.

In 2014, Nishikori made history when he reached the final of the Madrid Masters, and looked set to down world number one Nadal in the finale when he won the first set and led by a break in the second, but then disaster struck when a back injury forced him to retire in the third set. Less than two months earlier he had handed Djokovic a walkover in the semi-finals of the Miami Masters due to injury after downing Federer in the quarters.

The pattern has become clear: Nishikori struggles to play a handful of gruelling matches in succession. Even in his crowning moment, the 2014 US Open, Nishikori looked lacklustre in his defeat to Cilic in straight sets.

Speaking in 2014, one of Nishikori’s coaches, Dante Bottini, addressed the issue of his charge’s fitness.

“Maybe a little bit of Kei’s problem with injuries was mental,” Bottini conceded to tennis.com. “He didn’t really know how to deal with pain and injury. But he had some very long matches this year, against guys like David Ferrer (Madrid) and Roger Federer (Miami), and then at the U.S. Open. He dealt with those challenges much better, with a different mindset.

“His attitude now is, ‘Okay, I’m having pain, but I think I can deal with it.’ He knows his body better. He knows the difference between pain and injury, and how much he can push himself. Also, because he’s stronger physically he’s become mentally stronger and more able to withstand pain than before.”

However, last year Nishikori’s fragility began to reappear.

A calf injury that first appeared at the Halle Open recurred at Wimbledon, with the 26-year-old withdrawing from the tournament before his second round match. After reaching the semi-finals of the Rogers Cup Nishikori then pulled out of the Cincinnati Masters which followed, citing fatigue and hip injury. In the October he retired in the third round of the BNP Paribas Open due to an abdominal injury… and here we are again.

Nishikori’s talent is undoubted, he has a superb all-round game, but at 5ft 10in in a game dominated by big-hitting six footers is he too small to compete for the long-haul? Djokovic, Federer, Murray and even Nadal who is considered small for a top tennis player are over six foot.

While Nishikori’s coach, Michael Chang, is proof that dynamite – and successful dynamite at that – can come in small packages, the reality that Nishikori’s reliance on a baseline game full of powerful ground strokes is simply one is body might not be able to cope with.

At 26, it’s far too early to say Nishikori has hit his ceiling, but if he’s unable to bury his fitness gremlins once and for all, a first grand slam may continue to prove elusive.